Fluid dispenser having a rigid vial and flexible inner bladder

ABSTRACT

A dispenser for dispensing a fluid includes a rigid vial that has a main fluid chamber containing a fluid, and a pump assembly that is in fluid communication with the main fluid chamber and is configured to dispense a predetermined quantity of fluid from the main fluid chamber. A flexible bladder is provided which is located within the main fluid chamber and is configured to expand to fill the ullage created within the main fluid chamber during dispensing of fluid by the pump assembly. The resilient bladder tends to force itself outwardly toward the rigid vial and, in turn, increases the pressure within the main fluid chamber in comparison to the interior of the bladder to thereby prevent the ingress of air or vapors through the bladder or otherwise into the main fluid chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims the benefit of U.S. ProvisionalApplication Serial No. 60/242,595, filed Oct. 23, 2000, entitled “FluidDispenser Having A Rigid Vial And Flexible Inner Bladder”, and U.S.Provisional Application Serial No. 60/242,974, filed Oct. 24, 2000,entitled “Fluid Dispenser Having A Rigid Vial And Flexible InnerBladder”, both of which are hereby incorporated by reference as part ofthe present disclosure.

FIELD OF THE INVENTION

[0002] The present invention relates generally to dispensers fordispensing fluids or other substances and, more particularly, to adispenser having a rigid vial, a flexible bladder disposed within therigid vial and defining a chamber between the flexible bladder and rigidvial for receiving therein a fluid or other substance, and a nozzle andpump assembly coupled in fluid communication with chamber for dispensingfluids or other substances therefrom.

BACKGROUND INFORMATION

[0003] Typical fluid dispensers include a container defining therein achamber for receiving a fluid to be dispensed, a nozzle and pumpassembly mounted on the container, and a dip tube extending downwardlyfrom the nozzle into the chamber for pumping the fluid from the bottomof the chamber, through the dip tube, and out of the dispenser. Otherknown dispensers include a vial and a flexible bladder received withinthe vial. For example, U.S. Pat. No. 6,062,430 to Fuchs shows in FIG. 1a dispensing container with variable volume compensation including abottle-shaped vessel 2 in the form of a thin-walled, hollow body madefrom soft elastic plastic, and a reception container 15 formed of awrinkle film encapsulated within the vessel body 2.

[0004] One of the drawbacks associated with typical prior art fluiddispensers is that the fluid chamber(s) are not maintained in asubstantially airless condition throughout the storage, shelf lifeand/or usage of the dispenser. For example, the nozzles and/or valvesused in typical prior art dispensers frequently are incapable ofmaintaining the dispenser in a hermetically sealed condition. Suchnozzles and/or valves allow the passage of air or other gasestherethrough and into contact with the medicament or other substancecontained within the fluid chamber(s). In addition, such nozzles and/orvalves frequently allow vapor loss therethrough either during thestorage, shelf life or usage of the dispensers.

[0005] Another drawback associated with prior art dispensers is that thematerials of construction may undergo creep that, in turn, causes sealsformed within the dispensers to leak. Many medicaments are maintained instorage and/or on store shelves for at least several, and in someinstances, many months. During transportation and storage, thedispensers can be subjected to varying atmospheric conditions involvinglarge variations in atmospheric temperature, pressure and/or humidity.As a result, the dispensers are frequently subjected to substantialdifferential thermal expansion and/or contraction that, in turn, causethe materials of construction to undergo creep. The seals and othercomponents of such prior art dispensers typically are not designed toaddress such creep, and as a result, the dispensers develop leaks orotherwise allow air ingress and/or vapor loss when subjected to suchlong periods of storage or varying atmospheric conditions. For example,some polyethylene dispensers have been known to lose between about 10%to 25% of the weight of their contents during storage. Such weight lossis believed to be due to vapor loss from the medicament or otherfluid-containing chambers through the polyethylene walls of thedispensers and/or through leaks otherwise created in the seals or otherstructural interfaces of the containers. The vapor loss is typicallyoffset by air ingress into the chambers. Vapor loss and/or air ingressis particularly problematic for dispensers containing medicaments, suchas pharmaceutical preparations or vaccines, because they tend to diluteeach predetermined dosage of the medicament dispensed from thecontainer, and/or cause the dispenser to dispense inconsistentconcentrations of medicament from one dose to the next.

[0006] Yet another disadvantage associated with prior art dispensers isthat because they cannot reliably maintain the medicament or othersubstance contained therein in an airtight condition, they cannot beused for either multiple dose applications or preservative-freeformulations. The use of single dose dispensers can be substantiallymore expensive than multiple dose dispensers. In addition, thepreservatives used in many medicaments, such as pharmaceuticalpreparations and vaccines, can cause adverse reactions in patientsand/or dilute the effect of the medicament on the patient.

[0007] Another drawback of prior art dispensers is that the ullage or“dead space” inherent in such dispensers allows sediment build-up. Manymedicaments and other formulations contained within such dispensers aresuspensions. The ullage or dead space in the prior art dispensers allowsthe solutes or other solid components of such suspensions to formsediment therein. Such settling of the suspensions dilutes themedicaments or other substances contained within the dispensers and, inturn, alters the medicament and/or the concentration of medicament ineach patient dose.

[0008] Another drawback associated with many prior art dispensers isthat they can only dispense the medicament or other substance containedtherein in an upright or other single orientation. This drawbackprevents such dispensers from being used effectively in otherorientations, such as upside down. In addition, because such dispensersdo not maintain the medicament or other substance contained therein inan airless condition, they cannot be used in low gravity environments,such as outer space.

[0009] Accordingly, it is an object of the present invention to overcomeone or more of the above-described drawbacks and disadvantages of theprior art.

SUMMARY OF THE INVENTION

[0010] The present invention is directed to a dispenser for dispensing afluid. The dispenser comprises a rigid housing, and a flexible bladdermounted within the housing and defining an interior chamber within theflexible bladder, and a fluid-receiving chamber between the flexiblebladder and the rigid housing. The dispenser further comprises means forcreating a first pressure within the fluid-receiving chamber greaterthan a second pressure within the interior chamber of the bladder tothereby prevent the ingress of gases or vapors into the fluid-receivingchamber. In a currently preferred embodiment of the present invention,the means for creating the pressure differential is formed by aresilient material of the bladder that flexes the bladder outwardlytoward an expanded condition, and thereby creates the first pressurewithin the fluid-receiving chamber greater than the second pressure inthe interior chamber of the bladder. Preferably, the resilient bladderis molded in the expanded condition, and therefore the resilient bladderwill inherently tend to force itself into the expanded condition andthereby create the desired pressure differential between thefluid-receiving chamber and the interior chamber of the bladder.

[0011] A currently preferred embodiment of the dispenser furthercomprises a pump coupled in fluid communication with the fluid-receivingchamber for pumping a fluid received therein from the dispenser; and aone-way valve coupled in fluid communication with the pump for allowingthe passage of the pumped fluid therethrough and preventing the passageof fluids in the opposite direction. The one-way valve is preferablyformed by a nozzle, and a flexible cover overlying the nozzle andcreating the one-way valve at the interface of the nozzle and cover.

[0012] The preferred dispenser of the present invention furthercomprises a seal formed between the flexible bladder and the rigid vialfor sealing the fluid-receiving chamber. The seal includes a firstprotuberance extending radially outwardly on an outer surface of theflexible bladder, and a second protuberance axially spaced relative tothe first protuberance and extending radially inwardly on an innersurface of the bladder. The first and second protuberances are subjectto radial compression to seal the interface between the flexible bladderand rigid vial. Preferably, the first protuberance extends about anouter peripheral surface of the bladder and defines an outer annularsealing surface, and the second protuberance extends about an innerperipheral surface of the bladder and defines an inner annular sealingsurface. In addition, the first protuberance defines a tapered surfacefor directing bladder material in approximately the direction of thesecond protuberance to thereby facilitate maintaining a fluid-tight sealin the event of bladder material creep. The seal preferably furtherincludes a peripheral flange extending about an open end of the flexiblebladder and subject to axial compression for further sealing theinterface between the bladder and rigid vial.

[0013] The dispenser of the present invention further comprises a plugreceivable within an open end of the rigid vial and engageable with atleast one of the first and second protuberances for radially compressingthe protuberances to seal the interface between the flexible bladder andrigid vial. The plug defines at least one aperture therethrough in fluidcommunication with the interior chamber of the flexible bladder.Preferably, a two-way valve of the dispenser is coupled in fluidcommunication between the interior chamber of the flexible bladder andthe aperture of the plug for preventing fluid communication between theinterior chamber of the bladder and the ambient atmosphere when apressure differential across the two-way valve is less than a thresholdlevel. The two-way valve preferably is formed by a flexible, annularprotuberance extending radially inwardly from an inner peripheralsurface of the flexible bladder, and engageable with an annular surfaceof the plug to thereby seal the interface between the flexible bladderand plug. In a currently preferred embodiment of the present invention,the annular protuberance defines axially-opposed surfaces that taperinwardly in the radial direction to facilitate flexing of theprotuberance in response to the pressure differential across theprotuberance exceeding the predetermined threshold level.

[0014] The flexible bladder of the dispenser further defines an open endand a closed end, and is movable between a collapsed condition and anexpanded condition. Upon expansion of the flexible bladder from thecollapsed condition into the expanded condition, the flexible bladderand rigid vial define an annular gap therebetween. In a currentlypreferred embodiment, the annular gap defines an increasing width in theaxial direction from the open end toward the closed end of the flexiblebladder, to facilitate removal of fluid from the fluid-receiving chamberupon expansion of the bladder. Preferably, the flexible bladderinitially contacts the rigid vial adjacent to or near the open end ofthe bladder, and then progressively engages the rigid vial in the axialdirection from the open end toward the closed end of the flexiblebladder with further expansion thereof. Also in accordance with apreferred embodiment of the dispenser, the flexible bladder defines anexternal morphology in an expanded condition, the rigid vial defines aninternal morphology, and the external and internal morphologies aresubstantially the same to thereby allow the flexible bladder toconformably contact the rigid vial and substantially eliminate any deadspace in the fluid-receiving chamber therebetween.

[0015] In accordance with a preferred embodiment of the presentinvention, the pump of the dispenser comprises a piston, and a slide forslidably receiving the piston therein. At least one of the piston andthe slide is reciprocable relative to the other. In addition, the pistonis made of a relatively hard material, the slide is made of a relativelysoft material, and the piston causes a compression zone of the slide toflex outwardly upon moving at least one of the piston and the sliderelative to the other to thereby effect a fluid-tight seal between thepiston and slide. In addition, forming the slide from a relativelyflexible material allows the slide to be formed integral with a nozzle,such as by molding the two components in a single part, wherein theintegral nozzle and slide may be released from a core pin by injectingpressured air therebetween.

[0016] The dispenser of the present invention preferably furthercomprises means for controlling the flexible bladder to collapse into apredetermined collapsed condition. In one embodiment of the presentinvention, the means for controlling includes a plurality of legsextending axially inwardly into the interior chamber of the flexiblebladder for conformably contacting the flexible bladder upon collapsethereof. In another embodiment of the present invention, the means forcontrolling is defined by at least one axially elongated surfacediscontinuity formed in the flexible bladder.

[0017] In accordance with another embodiment of the present invention,the flexible bladder is capable of being penetrated by a needle or likeinjection member for introducing a predetermined substance into thefluid-receiving chamber. In this embodiment, the flexible bladderincludes a first portion substantially infusible in response to theapplication of thermal energy thereto and compatible with the substanceto be received within the fluid-receiving chamber, and a second portionoverlying the first portion and fusible in response to the applicationof thermal energy thereto. Thus, the second portion enables theformation of a substantially fluid-tight seal between the flexiblebladder and fluid-receiving chamber in a region thereof penetrated bythe needle or like injection member. In one embodiment of the presentinvention, the second portion is formed of either a thermoplastic or anelastomeric material, and the bladder, including the first portionthereof, is formed of vulcanized rubber.

[0018] One advantage of the dispenser of the present invention is thatthe pressure differential between the fluid-receiving chamber and theinternal chamber of the bladder and ambient atmosphere substantiallyprevents the ingress of air or other gases or vapors through theflexible bladder, or otherwise into the fluid-receiving chamber. As aresult, the dispensers of the present invention may maintain themedicaments or other substances contained therein in an airlesscondition throughout substantial periods of storage, shelf life and/oruse. Accordingly, the dispensers of the present invention areparticularly well suited for dispensing multiple doses of non-preservedmedicaments or other substances requiring storage in an airlesscondition.

[0019] Another advantage of the dispensers of the present invention isthat the seal formed between the flexible bladder and the rigid vialradially and axially directs the material of the flexible bladder topersistently maintain a fluid-tight seal regardless of any creep of thematerial during the storage or shelf-life of the dispenser. In addition,the one-way valve employed in the preferred embodiments of the presentinvention further maintains the fluid-receiving chamber in ahermetically-sealed condition throughout the storage, shelf-life and/oruse of the dispenser.

[0020] Yet another advantage of the dispensers of the present inventionis that because the medicament or other substance is maintained in anairless condition in the fluid-receiving chamber, the dispensers may beused in virtually any orientation, and furthermore, may be used in lowgravity environments.

[0021] Another advantage of the dispensers of the present invention isthat the flexible bladder preferably defines an external morphologysubstantially matching the internal morphology of the rigid vial. As aresult, the flexible bladder may expand and conformably contact therigid vial throughout the interface between these two parts and, inturn, eliminate any dead space within the fluid-receiving chamber.

[0022] Yet another advantage of the dispensers of the present inventionis that the two-way valve coupled in fluid communication between theinterior chamber of the flexible bladder and the ambient atmosphereprevents any exchange of gases or vapors between the interior chamber ofthe bladder and ambient atmosphere, provided the pressure differentialacross the valve is less than a predetermined level. As a result, thetwo-way valve creates a relatively stable micro-atmosphere within theinterior chamber of the flexible bladder, thus insulating the interiorchamber from fluctuations in pressure and/or humidity in the ambientatmosphere and thereby further preventing the ingress of gas or vaporsinto the fluid-receiving chamber.

[0023] Other objects and advantages of the present invention will becomeapparent in view of the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is a partially broken-away, perspective view of an oculartreatment apparatus having a dispenser mounted therein in accordancewith a preferred embodiment of the present invention.

[0025]FIG. 1A is a view similar to FIG. 1 absent the dispenser.

[0026]FIG. 1B is a perspective view of the ocular treatment apparatus ofFIG. 1.

[0027]FIG. 1C is an exploded view, in perspective, of the oculartreatment apparatus of FIG. 1B.

[0028]FIG. 1D is an exploded view, in side elevation, of the oculartreatment apparatus of FIG. 1B.

[0029]FIG. 2 is a side elevational view, partly in section, illustratingin further detail the dispenser of FIG. 1 including the pump assembly,vial and a bladder and wherein the pump assembly is disposed in a closedposition.

[0030]FIG. 3 is a view similar to that of FIG. 2, although the dispenseris rotated 90° with respect to its orientation in FIG. 2, and the pumpassembly is disposed in an extended position.

[0031]FIG. 4 is a central cross-sectional view taken along alongitudinal axis of a piston of the pump assembly of FIG. 1.

[0032]FIG. 5 is a front elevational view of a tip of a nozzle of thepump assembly of FIG. 1.

[0033]FIG. 6 is a longitudinal cross-sectional view taken along line 6-6of FIG. 5.

[0034]FIG. 7 is a central cross-sectional view taken along alongitudinal axis of a slide or body of the pump assembly of FIGS. 2 and3 and forming essentially the compression zone.

[0035]FIG. 8 is a central cross-sectional view taken along alongitudinal axis of a flexible pump cover of the pump assembly of FIGS.2 and 3, and illustrating the manner in which the pump cover extendsfrom the tip of the nozzle to the rigid vial and is configured to allowreciprocal movement of the piston connected to the vial.

[0036]FIG. 9 is a central, cross-sectional view taken along alongitudinal axis of the rigid vial of the dispenser of FIGS. 2 and 3.

[0037]FIG. 9A is an enlarged view of a portion of the vial of FIG. 9showing a rear mounting portion for receiving the bladder of FIG. 10.

[0038]FIG. 10 is a central, cross-sectional view taken along alongitudinal axis of the bladder of the dispenser of FIGS. 2 and 3showing in this configuration a three-ribbed structure provided to allowthe bladder to collapse into a predetermined collapsed condition.

[0039]FIG. 10A is an enlarged view of a portion of the bladder of FIG.10.

[0040]FIG. 10B is a highly enlarged view of a portion of the bladder ofFIG. 10.

[0041]FIG. 11 is a cross-sectional view taken along a transverse axis ofthe bladder of FIG. 10.

[0042]FIG. 12 is a schematical view showing, in cross section, anotherembodiment of the bladder of the dispenser of FIGS. 2 and 3 disposedwithin the rigid vial and including elongated discontinuities orelongation buffers disposed in an outer wall of the bladder tofacilitate the collapse of the arcs that pass through the chords of therespective arcs.

[0043]FIG. 13 is a top plan view of the rear plug employed to close therear end of the inner bladder by forming a sandwich-type structurebetween the rigid vial and rear plug to hermetically seal the dispenserof FIGS. 2 and 3.

[0044]FIG. 14 is a sectional view of the rear plug taken along line14-14 of FIG. 13.

[0045]FIG. 14A is an enlarged portion of the rear plug of FIG. 14showing further detail of an annular side wall of the plug.

[0046] FIGS. 15A-C are sequential side elevational views, partly insection, showing the reduction in volume of fluid and correspondingexpansion of the bladder in the full, half-full and empty conditions ofthe dispenser of FIG. 1, respectively.

[0047] FIGS. 16A-C are sequential side elevational views, partly insection, showing the steps of assembling the bladder to the vial duringsterilization and filling of the dispenser of FIGS. 2 and 3.

[0048]FIG. 17 is a perspective view of another embodiment of a dispenserof the present invention.

[0049]FIG. 18 is an end elevational view of the dispenser of FIG. 17.

[0050]FIG. 19 is a cross-sectional view of the dispenser of FIGS. 17 and18 taken along line 19-19 of FIG. 18.

[0051]FIG. 20 is a cross-sectional view of the dispenser of FIGS. 17 and18 taken along line 20-20 of FIG. 18.

[0052]FIG. 21 is a perspective view of the rear plug of the dispenser ofFIG. 17.

[0053]FIG. 22 is cross-sectional view of the rear plug of FIG. 21.

[0054]FIG. 23 is a partial, enlarged cross-sectional view of the rearplug of FIG. 21.

[0055]FIG. 24 is a partial, cross-sectional view of theaxially-extending and radially-projecting legs of the rear plug of FIG.21 illustrating the flexible bladder conformably engaging the legs inthe predetermined collapsed condition.

[0056]FIG. 25 is a partial, cross-sectional view of the legs of the rearplug and bladder illustrating the bladder in the expanded condition.

[0057]FIG. 26 is a cross-sectional view of the flexible bladder of thedispenser of FIG. 17.

[0058]FIG. 27 is a partial, enlarged cross-sectional view of a portionof the flexible bladder of FIG. 26.

[0059]FIG. 28 is a front elevational view of the integral nozzle andslide of the dispenser of FIG. 17.

[0060]FIG. 29 is a cross-sectional view of the integral nozzle and slidetaken along line 29-29 of FIG. 28.

[0061]FIG. 30 is a side elevational view of the integral piston andrigid vial of the dispenser of FIG. 17.

[0062]FIG. 31 is a partial, cross-sectional view of the integral pistonand rigid vial of FIG. 30.

[0063]FIG. 32 is a cross-sectional view of the flexible nozzle cover andbellows of the dispenser of FIG. 17.

[0064]FIG. 33 is a cross-sectional view of another embodiment of thedispenser of the present invention including a resealable portion on theflexible bladder for inserting a needle or like injection membertherethrough to fill the dispenser with a medicament or other substance,and allowing the needle holes to be sealed by application of thermalenergy thereto.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] In FIG. 1, there is shown an ocular treatment apparatus 8 thatmay be used in conjunction with a dispenser, shown generally at 10, inaccordance with the present invention. As seen in FIGS. 1 and 1A, thetreatment apparatus 8 comprises a housing 12 that may be generallyU-shaped in cross section, and defines an interior cavity 14 and an eyecover 16. A trigger 18 is pivotally connected at one end 20 to thehousing 12 via a hinge 22, and includes at the other end an arm portion24 defining a slot 25. As shown best in FIG. 1A, a pin 26 of a wheel 27is fixedly secured within the slot 25, and the wheel 27 is rotatablymounted on the interior wall of the housing 12. As best seen in FIG. 1,the trigger 18 is elongated and comprises finger grooves 28 for acomfortable fit with, e.g., a patient's hand. An approximately L-shapedspring arm 30 is fixedly secured at one end to a post 29 projectinginwardly from the interior wall of the housing 12, and the spring armdefines a knee or bent portion 31 (shown in phantom) engaging aninterior surface of the trigger 18, and a free end 32 engageable with arim 34 formed at one end of the dispenser 10. An eyelid depressor 36 ispivotally mounted by a hinge 38 to the end of the housing 12 adjacent tothe eye cover 16, and includes a hook 40 fixedly secured to the wheel 27for pivotally moving the eyelid depressor upon actuating the trigger 18.

[0066] In use, the eye cover 16 is placed adjacent to the tissuesurrounding the eye with the eyelid depressor 36 engaging the tissueadjacent to the ocular cul-de-sac. Upon squeezing the trigger 18, theeyelid depressor 36 rotates in the direction of the arrow 41, and inturn moves the tissue adjacent to the eye to expose the ocularcul-de-sac. Rotation of the eyelid depressor 36 is caused by the wheel27 which also uncovers a nozzle 42 formed at the adjacent end of thedispenser 10. Simultaneously, the spring arm 30 forces the rim 34 of thedispenser 10 away from the fixed nozzle 42 to thereby prime the pump ofthe dispenser, as described in further detail below. Upon squeezing thetrigger 18 and correspondingly extending the dispenser 10 within thehousing 12, the free end 32 of the spring arm 30 eventually disengagesitself from the rim 34 of the dispenser to thereby release the extendeddispenser from the spring arm. As a result, due to the resiliency orspring-like nature of the nozzle 42, as described further below, theextended dispenser contracts or moves back toward the nozzle and, inturn, releases a predetermined dosage of medicament (or other substance)from the nozzle and into the ocular cul-de-sac of the user's eye. Then,when the user removes the ocular treatment apparatus 8 from his or hereye and releases the trigger 18, the spring arm 30 automatically returnsto its original or resting position as shown in FIG. 1 with the free end32 engaging the rim 34. The force exerted by the spring arm 30 uponreturning to its original position also rotatably drives the wheel 27 inthe direction opposite that of the arrow 41 and, in turn, causes theeyelid depressor 36 to return to its original position, as shown. Theocular treatment apparatus is then ready to dispense anotherpredetermined dosage of medicament or other liquid contained therein.

[0067] Other examples of ocular treatment apparatus that may employ thedispenser 10 are described in U.S. Pat. Nos. 4,981,479 and 6,033,384,which are assigned to the assignee of the present invention and arehereby incorporated by reference as part of the present disclosure.Accordingly, as may be recognized by those of ordinary skill in thepertinent art based on the teachings herein, the dispensers of thepresent invention may be utilized in any of numerous different apparatusor systems to facilitate holding and dispensing medicaments or otherfluids, liquids or other substances contained therein, such as nasalinhalers.

[0068] Referring now to FIGS. 2 and 3, the dispenser 10 is shown partlyin cross section to illustrate the internal components thereof. Thedispenser 10 is generally cylindrical in outer configuration andcomprises a pump assembly 50, a generally rigid vial 52, and a flexiblebladder 54 disposed within a main fluid chamber 55 of the vial. The pumpassembly 50 comprises a piston 56 for discharging predetermined doses ofmedicaments or other substances contained within the fluid chamber 55, aslide or body 60 for slidably receiving therein the piston and defininga predetermined dosage chamber therebetween, and a pump cover 62 formingwith a nozzle 58 a one-way valve at the dispensing tip and a spring-likebellows for allowing either the piston or nozzle to be moved toward theother to eject a dose of medicament or other substance through thenozzle, and to force either the piston or the nozzle away from the otherupon releasing the predetermined dose. The nozzle 58 hermetically sealsthe dispensing tip of the dispenser and ejects the pumped medicament orother substance therethrough.

[0069] Referring now also to FIG. 4, the piston 56 may be composed ofany durable and moldable material, such as a plastic substance and,preferably, the material is suitable for use in connection withmedicaments. A suitable material is a low density polyethylene. Thepiston 56 comprises a base portion 64, an elongated portion 66 extendingfrom the base portion 64, and a central bore 68 which is in fluidcommunication with the main fluid chamber 55. The base portion 64 isgenerally disc-like in outer configuration, and comprises a connectingflange 70, an annular mounting portion 72, a first annular groove 74,and a second annular groove 76 spaced inwardly relative to the firstannular groove and surrounding the inlet end of the central bore 68. Theconnecting flange 70 is configured to engage, e.g., in a snap-lockmanner, the vial 52 defining a correspondingly dimensioned mountingflange 78 (FIG. 2). As shown in FIG. 2, the mounting portion 72 andfirst annular groove 74 receive an annular flange 80 and rib 82,respectively, of the pump cover 62 which is composed of a flexiblematerial, as discussed in more detail below, and which thereby seals themain fluid chamber 55 of vial 52. As further shown in FIG. 2, when thepiston 56 is assembled to the vial 52, the second annular groove 76 islocated adjacent to the main fluid chamber 55. The second annular groove76 thereby functions to provide a capture area to receive any gasbubbles improperly disposed within the main fluid chamber and to preventthe bubbles from passing into the central bore 68.

[0070] As shown best in FIG. 4, the elongated portion 66 comprises anannular groove 84, a laterally-extending bore 86, and a terminal enddefining a receptacle portion 88. The annular groove 84 is configured toreceive a seal 90 (FIG. 2), such as an o-ring, for sealing the piston incontact with the slide 60. The laterally extending bore 86 is in fluidcommunication with the central bore 68 and terminates adjacent to anannular interior surface 92 of the slide 60 (FIG. 3). As shown best inFIG. 4, the receptacle portion 88 comprises an annular wall 94, atapered portion 95 extending between the annular wall 94 and bore 86,and a piston surface 96 for stopping movement of the nozzle 58 asdescribed in more detail below in connection with FIGS. 5 and 6. Theannular wall 94 defines a generally increasing outer diameter toward thedistal end, and slidably engages the annular interior surface 92 of theslide 60 as described in more detail below in connection with FIG. 7.

[0071] As shown in FIG. 3, the piston 56 further includes two generallysymmetrically-located hook portions 97, and each hook portion 97 definesin combination with an outer surface 101 of the piston 56 a respectiveslot 99. As described in more detail below in conjunction with FIG. 7,the slide 60 is reciprocally disposed within the slots 99 for allowingrelative movement of the piston within the slide upon actuation of thepump.

[0072] Referring now to FIGS. 5 and 6, the nozzle 58 may be composed ofany suitably durable, moldable, somewhat flexible material (in theconfiguration wherein the nozzle and body are made of one piece), suchas a plastic material, and currently is composed of a material which hasbeen found to be compatible with medicaments, such as those materialssold under the trademarks VELEX and LEXAN, both owned by the GeneralElectric Company of Pittsfield, Mass. The nozzle 58 is preferably moldedof one piece and comprises a truncated, conical-shaped body portion 98,and a disc portion 100 disposed coaxially with the conical-shapedportion and extending radially therefrom. It will be recognized that theconical-shaped portion 98 and disc portion 100 may be molded together orseparately. The conical-shaped portion 98 comprises a tapered outersurface 102, a partial central bore 104, and an engagement portion 106.The partial central bore 104 terminates at a lever wall 108 which isdimensioned and configured to allow flexing of the tapered outer surface102 in the direction of the arrow 110. The engagement portion 106 isconfigured to mate with the receptacle portion 88 of the piston 56,described above in connection with FIG. 4, and comprises a truncatedconical configuration terminating in an engagement surface 112. Asillustrated in FIGS. 2 and 3, when the piston 56 reaches the end of itsstroke upon dispensing a predetermined dose, the engagement surface 112of the nozzle is received within the guide wall 94 and engages thepiston surface 96 to terminate further movement. It will be recognizedthat a variable stroke volume 113 is defined between the engagementsurface 112 of the nozzle 58 and the piston surface 96 of the piston 56.As illustrated in FIG. 3, the maximum stroke volume is defined by themaximum extension of the engagement surface 112 from the piston surface96.

[0073] As shown in FIG. 6, the disc portion 100 comprises an annularmounting portion 114 for affixably mounting the nozzle 58 to the pumpcover 62 and slide 60 (FIGS. 2 and 3), and also comprises a slot 116 forthe passage of fluid or other substances therethrough. The mountingportion 114 comprises an annular thickened portion 118 and a neckportion 120 disposed between a pair of annular grooves 122 and 124. Asshown in FIGS. 2 and 3, the annular groove 122 is configured to engage arib 126 of the pump cover 62 (FIG. 8), and the annular slot 124 isconfigured to engage a correspondingly configured terminal end portion128 of the slide 60 (FIG. 7). As shown in FIG. 6, the annular groove 124defines an annular crevice 130, employed, e.g., for easing assembly ofthe slide 60 to the nozzle 58. The slot 116 is disposed adjacent to aflattened portion 132 of the tapered outer surface 102, and providesfluid communication from the variable stroke volume 113 through the discportion 100 to the tapered outer surface.

[0074] As illustrated in FIG. 7, the slide 60 defines a tubular body andmay be composed of a similar substance to that described above withrespect to the nozzle 58 (FIGS. 5 and 6). As described above andreferring also to FIG. 2, the slide 60 comprises an annular insidesurface 92 within which the piston 56 and engagement portion 106 of thenozzle 58 are disposed after assembly of the dispenser 10. The insidesurface 92 defines a bore 134 with a neck portion 136 of reduceddiameter disposed between a first transition zone 138 of relativelyrapid increase in diameter, and a second transition zone 140 ofrelatively gradual increase in diameter. Referring now to FIG. 2, itwill be understood that during relative movement of the nozzle 58 andthe slide 60 away from the piston 56, the annular wall 94 of the piston(FIG. 4) will engage the second transition zone 140 (FIG. 7) in sealingengagement to thereby force fluid contained within the variable strokevolume 113 into the slot 116 of the nozzle tip.

[0075] With reference to FIG. 7 and as described above in connectionwith FIGS. 5 and 6, the slide 60 defines a terminal end 128 thatincludes an annular ridge 142 configured to engage the crevice 130 ofthe nozzle 58. As shown in FIG. 3, the opposite end of the slide 60defines a flange 144 that is configured to engage the hook portion 97 ofthe piston 56.

[0076]FIG. 8 depicts a cross-sectional view of the flexible pump cover62. The flexible pump cover 62 may be composed of any durable, resilientand flexible material, such as an elastomeric material. Preferably, thepump cover 62 is composed of a thermo-elastic material, such as astyrene-butadiene elastomer sold under the trademark KRATON by GLS ofIllinois. Other suitable materials include polyvinylchloride,Santoprene™ and butyl rubber. The pump cover 62 comprises a mountingportion 146, a bellows portion 148, and a nozzle cover 150 whichcooperates with the slot 116 (FIG. 6) to provide an elastic valve, asdescribed further below in connection with FIG. 5. As described above inconnection with FIG. 4, the mounting portion 146 comprises an annularflange 80 that fits within the mounting groove 72 adjacent to themounting flange 78 of the vial 52 (FIG. 2). As shown in FIG. 8, the rib82 defines in cross section a truncated conical shape corresponding tothe configuration of the annular groove 74 of the piston (FIG. 4).Because of the resilient nature of the material of the pump cover 62,the annular flange 80 may be slightly oversized in order to provide aresilient fit with the vial 52 and piston 56 and thereby, in combinationwith the rib 82, hermetically seal the main fluid chamber 55 (FIG. 2).

[0077] The bellows portion 148 extends between the mounting portion 140and nozzle cover 150, and comprises a plurality serpentine or inverselycurled portions 152 which function to provide resiliency in a directiongenerally parallel to a central axis 154 and sufficient spring-likeforce to either drive the piston or the nozzle away from the other andreturn the piston to the top of its stroke upon dispensing apredetermined dose of a medicament or other substance contained withinthe chamber 55. Referring also to FIGS. 2 and 6, the nozzle cover 150,when mounted, is dimensioned and configured to resiliently engage thenozzle 58 and slide 60, and includes the annular rib 126 extendingaxially from a disc engagement portion 156. The disc engagement portion156 is disposed between a slide engagement portion 158 and a nozzle bodyengagement portion 160. Referring also to FIG. 6, the nozzle bodyengagement portion 160 is configured to engage the tapered outer surface102 of the nozzle 58 to thereby form a normally-closed, one-way valvetherebetween. As can be seen in FIG. 8, the cross-sectional thickness ofthe nozzle engagement portion 160 gradually decreases in the axialdirection from the disc engagement portion 156 toward the dispensing tip161. The gradually-decreasing cross-sectional thickness of the nozzleengagement portion 160 facilitates the release of the medicament orother substance through the one-way valve formed by the elongated,annular interface between the relatively flexible nozzle engagementportion 160 of the cover and the tapered surface 102 of the nozzle body,while simultaneously preventing air or other gases from passing throughthe valve in the opposite direction, in accordance with the teachings ofthe below-mentioned patents incorporated by reference herein.

[0078] In operation, as described above in connection with FIGS. 1 and1A, movement of the vial 52 in the axial direction causes the piston 56to move from the position shown in FIG. 2 into the position shown inFIG. 3 (or vice versa), e.g., by actuating the trigger 28 of FIG. 1 orother actuator, which draws fluid into the variable volume fluid chamber113 from the main fluid chamber 55 via the central bore 68 andlaterally-extending bore 86 of the piston. Referring now also to FIGS. 6and 8, as the piston 56 moves toward the nozzle 58 (or vice versa), thefluid is injected through the slot 116 (FIG. 6), along the flattenedsurface 132, between the tapered surface 102 and nozzle body engagementportion 160, and then outwardly of the nozzle tip. Further details ofpump assemblies that may be used in the practice of the presentinvention are described in U.S. Pat. Nos. 5,944,702, 5,875,931 and5,746,728, which are assigned to the same assignee as the presentinvention, and are hereby expressly incorporated by reference as part ofthe present disclosure.

[0079] One advantage of the pump configuration of the illustratedembodiment, and as indicated by the arrow indicating the path of fluidflow in FIG. 6, the pumped fluid follows a fairly straight pathextending in a direction parallel to the axis 154 from the variablestroke volume 113, over the tapered surfaces of the engagement portion106, through the slot 116, and between the one-way valve formed by theinterface of the nozzle engagement portion 160 of the cover and thetapered outer surfaces 132 and 102 of the nozzle body. This relativelystraight and smooth fluid flow path allows the pumped fluid to flowthrough the nozzle with relatively little head loss, thus allowinglesser force to dispense the fluid and otherwise facilitating precisecontrol over the type of fluid flow to be emitted at the dispensing tip,such as control over drop size, flow velocity, or spray droplet size,spray pattern, etc.

[0080] Yet another advantage of the illustrated pump configuration isthat the bellows 148 is sealed relative to the variable-stroke volume113 to thereby prevent any of the medicament or other substancecontained within the chamber 55 from collecting in the space between thebellows and the piston or slide. As can be seen, the o-ring or like seal90 forms a fluid-tight seal between the piston and the slide, thuspreventing any fluid from flowing therethrough and into the bellows.Similarly, fluid-tight seals are formed at the interfaces of the cover62, nozzle 58 and slide 60, including fluid-tight seals at theinterfaces of the slide engagement portion 158 of the cover and theslide 60, and at the interface of the annular rib 126 of the cover andat the annular groove 122 of the nozzle 58.

[0081] Referring now to FIGS. 9 and 9A, the vial 52 is preferablycomposed of a suitably rigid and moldable material, such as a rigidpolymeric material, e.g., polycarbonate or polyvinylchloride.Preferably, this material is selected to be compatible with a widevariety of medicaments, such as that sold under the trademark Lexan ofthe General Electric Corporation of Pittsfield, Mass. The vial 52 istubular in configuration and comprises an outer wall 77 that defines themain fluid chamber 55, the annular mounting flange 78 discussed above inconnection with FIGS. 2 and 4, and an annular connecting portion 162formed on an opposite end of the vial relative to the mounting flange78. The main fluid chamber 55 is dimensioned such that it is largeenough to contain a predetermined quantity of a fluid to be dispensed,such as a medicament, along with the flexible bladder 54 (FIG. 2)discussed in more detail below. The mounting flange 78 includes anannular ridge 164 for mounting the vial 52 into sealing engagement withthe nozzle cover 62 (FIG. 2) and preventing movement of the cover duringuse of the dispenser 10. As seen in FIGS. 2 and 3, the mounting portion146 of the cover 62 is sandwiched between the base 64 of the piston 56and the rigid vial 52 to form a fluid-tight seal.

[0082] As shown in FIG. 9A, the annular connecting portion 162 comprisesa tapered end 166 and a peripheral groove 168 spaced inwardly therefromon an increased diameter portion 170. An annular ridge 172 is providedfor engaging the flexible bladder 54 (FIG. 2). As described furtherbelow, the increased diameter portion 170 and annular ridge 172 functionto allow hermetic sealing of the main fluid chamber 55 after assembly ofthe vial 52. As also described further below, an annular groove 174 isprovided for retention of the vial 52 during filling of the main fluidchamber 55.

[0083] Referring now to FIG. 10, the flexible bladder 54 may be composedof any suitably flexible material, and preferably defines barrierproperties to prevent the passage therethrough of vapor, moisture andgas. For ease of manufacture, the material preferably may be molded andis compatible with a wide variety of medicaments or other substances tobe contained within the chamber 55, and therefore in a preferredembodiment may be formed of a rubber or synthetic rubber. Alternatively,the flexible bladder 54 may be composed of a thermo-elastic material,such as the styrene-butadiene elastomer sold under the trademark KRATONas discussed above in connection with the pump cover 62. Similarly,materials sold under the trademarks VISKAFLEX owned by the AES Company,ALCRYN or HYTREL owned by the Dupont Company of Wilmington, Del., andSARLINK owned by the DSM Company may be used instead. These materialsare only exemplary, however. As may be recognized by those skilled inthe pertinent art based on the teachings herein, the flexible bladdermay be made of any of numerous other materials that are currently orlater become known for performing the function of the flexible bladderas disclosed herein.

[0084] In the preferred embodiments of the present invention, theflexible bladder 54 is made of a resilient material as described aboveand is molded in the expanded condition. Accordingly, when collapsed inthe manner described further below, the resilient bladder tends to forceitself outwardly and, in turn, increase the pressure of the medicamentor other fluid in the main fluid chamber 55 in comparison to thepressure in the interior of the bladder. A significant advantage of thispressure differential is that it facilitates in preventing the ingressof air, other gases or vapors located within the interior chamber of thebladder through the bladder or otherwise into the main fluid chamber. Asa result, the dispensers of the present invention are particularly wellsuited for containing multiple dose, non-preserved medicaments or othersubstances, and in maintaining such substances in a sterile, airlesscondition, throughout substantial periods of storage, shelf life and/oruse of the dispensers. This advantageous feature also facilitates inpreventing any changes in the ambient conditions of the dispenser fromaffecting the airless condition of the main fluid chamber 55, andotherwise prevents the ingress of air, other gases or vapors into themain fluid chamber.

[0085] The flexible bladder 54 preferably also provides a barrier to thepassage of gas, such as air, through the flexible bladder, and thus maybe composed of a single layer of material that has a substantiallyreduced permeability to air. In one embodiment of the present invention,the bladder 54 is composed of a multi-layered material. For example, asillustrated in FIG. 10B, a bladder wall 175 may comprise a firstflexible layer 177 of an elastomer that is relatively porous to air, anda barrier layer 179, such as a metallized MYLAR, e.g., an aluminum andpolyester composition, sold by the Dupont Corporation of Wilmington,Del., that is relatively impervious to air. The barrier layer 179 may bedisposed between a polyethylene upper layer 181 and lower layer 183 tofacilitate adhesion of the barrier layer to the bladder wall 175 whilemaintaining flexibility. Alternatively, the barrier layer 179 may becomposed of polyvinylidene chloride sold under the mark SARAN owned bythe Dow Chemical Company of Midland, Mich. It will be appreciated thatthe barrier layer 179 is preferably dimensioned to cover as much of thebladder wall 175 as permitted in order to reduce the passage of airtherethrough without interfering with the various functions of theflexible bladder as more fully described below. The barrier layer 179 isalso preferably disposed on the interior of the bladder wall 175.Optionally, the barrier material may be a butyl rubber-based material,such as that used for the manufacture of syringe stoppers, or used inthe tire industry. As may be recognized by those skilled in thepertinent art based on the teachings herein, the flexible bladder andbarrier materials disclosed herein are only exemplary, and any ofnumerous other materials that are currently known, or later become knownfor performing the functions disclosed herein, may be equally employed.

[0086] Referring now again to FIG. 10, the flexible bladder 54 istubular in configuration and comprises a closed end 176 and an open end178 that fluidly communicates with a cavity 180. The bladder 54 definesan external diameter dimensioned to fit within the vial 52 (FIG. 2) whenin the expanded condition as shown in FIG. 10. As shown in FIGS. 2 and3, the outer surface of the bladder 54 preferably defines a shape ormorphology substantially the same as that of the interior surface of therigid vial 52 so that upon expanding the flexible bladder, the flexiblebladder conforms to and contacts the rigid vial throughout the interfaceof these two components to thereby eliminate any ullage or dead spacebetween the components, and force all of the medicament or othersubstance within the chamber 55 into the variable stroke volume 113 ofthe pump 50 for dispensing therefrom. In addition, the outer diameter(or width) of the flexible bladder when fully expanded is preferablyslightly greater than the inner diameter (or corresponding width) of therigid vial, so that the expanded bladder may exert a resilient forceagainst the vial to maintain at least a slight pressure differentialbetween the chamber 55 on one side of the bladder and the interior ofthe bladder and thereby prevent the ingress of air, other gases orvapors through the bladder and into the main fluid chamber, as describedabove.

[0087] As shown in FIGS. 10 and 11, longitudinally extending stiffenersor rib portions 182 are disposed along the inside surface 184 andfunction to provide a supporting structure 2 about which the bladder 54may collapse as will be described in more detail below in conjunctionwith FIG. 12. To achieve this, the rib portions 182 extend axially alongthe interior surface 184 and are approximately equally spaced about thecircumference of the interior surface. It will be recognized that otherconfigurations of the rib portions 182 and/or locations at which the ribportions may be employed are contemplated by the present invention. Forexample, the rib portions 182 also may extend along the inside surface183 of the closed end 176 of the flexible bladder 54.

[0088] As illustrated in FIGS. 10 and 10A, the flexible bladder 54includes a mounting portion 186 that comprises an annular flange 188formed at the rear end of the bladder, an outer annular lobe 190 spacedaxially inwardly relative to the flange 188, and an inner annular lobe192 spaced between the outer annular lobe 190 and the flange 188. Asshown in FIG. 10A, the annular flange 188 defines on its underside anannular, V-shaped indent 194 for sealing engagement with the annularridge 172 of the vial 52 (FIG. 9A). In addition, the annular flange 188is over-sized so that during initial assembly with the vial 52, as willbe discussed in more detail below, the peripheral surface of the annularflange may engage the corresponding annular groove 168 of the vial 52(FIG. 9A).

[0089] During storage and/or shelf life of the dispenser 10, thematerial of the flexible bladder 54 may flow or move in order toequalize the tensile and compressive forces that it is subject to.Creep, as used herein, refers to a change in property of the materialwherein there is a loss in resilience and memory of the material. Inparticular, after undergoing creep the elastic material may permanentlydeform and lose at least some of its original elasticity. Accordingly,after assembly and during filling of the dispenser 10, the cavity 180 ofthe flexible bladder 54 may be subject to low pressure which causescollapse and elastic deformation thereof which is maintained by thepressure of fluid filled in the main fluid chamber 55 (FIG. 2).Thereafter, the filled dispenser may be maintained in storage and/or ona store or other shelf for at least two or more months prior to use,during which the material of the bladder may undergo creep causing atleast some deformation thereof. To properly manage the movement of thematerial during creep of the flexible bladder 54, and as shown best inFIG. 10A, the bladder is provided with the outer annular sealing lobe190 and the inner annular sealing lobe 192 spaced axially between theouter sealing lobe and the flange 188 so that, when creep resulting fromcompression of the elastomeric or rubber-like material occurs, the intramaterial pressure is balanced in between the two lobes 190,192 and apersistent, fluid-tight seal is provided. This mechanical seal can thenbe maintained due at least in part to the material reservoir formed bythe inner lobe 192 in which creeping material in the outer lobe 190offsets that of the inner lobe.

[0090] As shown in FIG. 10A, the outer annular lobe 190 comprises afirst angular portion 198 located on one side of the lobe 192, and asecond angular portion 200 disposed on the opposite side of the lobe.The first angular portion 198 defines a first acute angle “A” withrespect to a center axis 202 that may be within the range ofapproximately 0° to approximately 30°, and more preferably within therange of approximately 0° to approximately 10°. The second angularportion 200 defines a second acute angle “B” relative to the axis 202that may be within the range of approximately 0° to approximately 15°,and more preferably within the range of approximately 0° toapproximately 5°. In order to ensure that during creeping of thematerial of the flexible bladder 54 the material moves approximately inthe directions of the arrow 204 and arrow 205, the first angle A islarger than the second angle B and the flexible bladder is axially fixedby the inner annular sealing lobe 192 received within the correspondingannular groove 22 of the rear plug (FIG. 14). As shown in FIGS. 2 and 3,when the flexible bladder 54 is fully received within the rigid vial 52,the outer annular lobe 190 is pressed against the smooth interior wallof the vial, the inner annular lobe 192 is received within thecorresponding annular groove 22 of the rear plug (FIG. 14), and theannular flange 188 is sandwiched between the rear plug and the annularridge 172 of the rigid vial. Thus, the inner annular sealing lobe 192functions as a material reservoir for the outer annular sealing lobe190, and as indicated by the arrows 204 and 205, the axially-offsetlobes cause the material to flow generally from the outer lobe 190toward the inner lobe 192, and from both lobes generally toward theannular flange 188. As a result, the material flow is persistentlydirected toward the inner sealing lobe 192 and/or annular flange 188 tothereby maintain a fluid-tight seal between the flexible bladder, rigidvial and rear plug, regardless of the degree of creep of the bladdermaterial. As can be seen, the shape and relative position of the outerannular lobe 190 as described above facilitates in directing the forceswithin the bladder and thus the material in the directions of the arrows204 and 205 to thereby maintain the fluid-tight seal throughout thestorage, shelf-life and usage of the dispenser 10.

[0091] As shown in FIG. 11, the flexible bladder 54 preferably alsocomprises at least one surface discontinuity 206 that facilitates andcontrols the collapse of the bladder from a tubular configuration to apredetermined collapsed configuration to thereby substantially eliminatethe volume of the cavity 180 defined by the interior of the bladder. Inthe illustrated embodiment, the flexible bladder comprises three surfacediscontinuities 206 located on the interior surface 184 of the bladderand approximately equally spaced relative to each other. As can be seen,the discontinuities 206 are each approximately equally spaced betweenadjacent elongated ribs 182. The discontinuities 206 are illustrated inthe configuration of a crevice or crack terminating in a generally flatcenter portion (not numbered) in cross section as shown. As can be seen,the surface discontinuities 206 cause the bladder to collapse or foldonto itself about each elongated rib 182 to thereby form in thecollapsed condition three folded sections or legs spaced about 120°relative to each other. As may be recognized by those skilled in thepertinent art based on the teachings herein, and illustrated by theadditional embodiments below, any of numerous other structures orconfigurations may be equally employed to collapse the bladder into apredetermined shape, such as the predetermined collapsed shape formed bydiscontinuities and elongated ribs described above.

[0092] Referring now to FIG. 12, a cross section of an outer wall 208′of a flexible bladder 54′ is illustrated in schematic. The flexiblebladder 54′ is capable of collapsing in the direction of arrows 210′from an expanded position, shown in solid lines adjacent to the outerwall 77 of the vial 52 (FIG. 9) to a collapsed position shown in brokenlines. The flexible bladder 54′ is functionally similar to the flexiblebladder 54 and thus like elements are labeled with like referencenumerals followed by the prime (′) symbol. However, it will berecognized that some differences in structure exist between the flexiblebladder 54 and the flexible bladder 54′. For example, discontinuities206′ are illustrated as being inverted with respect to thediscontinuities 206 and generally cover the entire cross-sectionalthickness (t′) of the wall 208′. While the discontinuities 206′ areillustrated as generally arcuate in configuration, it will beappreciated that other configurations, such as that of discontinuities206, which also perform the function described below may be employedinstead. Also, it will be appreciated that the rib portions 182′ definemounting slots 209′ for receiving therein correspondingly-shapedportions (not shown) of the vial 52.

[0093] It will be understood that both the discontinuities 206 and 206′function to allow for a reduction in length of the portions of the wall208′ necessary to collapse the flexible bladders 54 and 54′. While thisfunction is being described in connection with the embodiment of FIG.12, this description is equally applicable to the embodiment of FIG. 11.As shown in FIG. 12, the wall 208′ comprises a plurality of wallportions 212′ extending between each discontinuity 206′ and adjacent ribportion 182′, and as shown in solid lines each wall portion 212′ formsan arc when the bladder 54′ is expanded. It will be recognized thatduring collapsing of the bladder 54′ in the directions of the arrows210′, the wall portions 212′ become approximately linear and form achord as shown in the dashed and dotted lines, and then inverselyarcuate as illustrated in the dashed lines. Accordingly, as illustrated,a length L₁ of the discontinuities 206′ shown in solid lines shortens toa length L₂ shown in dotted and dashed lines to thereby allow freemovement of the arcs 212′ in the direction of the arrows 210′. Once theflexible bladder 54′ has collapsed, the bladder may expand and the wallportions 212′ may freely move in a direction opposite that of the arrows210′.

[0094] As illustrated in FIGS. 13 and 14, the flexible bladder comprisesa rear plug 214 configured to mate with the open end 178 of the flexiblebladder 54 (FIG. 2) and to seal the flexible bladder 54 disposed betweenthe rear plug and the rigid vial 52. The rear plug 214 may be composedof any suitably strong, moldable and durable material, such as apolymeric material, e.g., polyethylene, and is preferably composed ofLexan™ or a like polycarbonate for its stress-resistant properties. Therear plug 214 comprises an end wall 216 and a side wall 218 that, asseen best in FIG. 14A, preferably includes a tapered portion 220defining a gradually increasing diameter in the direction of the rearend of the plug, an annular groove 222 spaced rearwardly of the taperedportion 220, a stepped portion 224, a plurality of outwardly-protrudingprotective tabs 226 (or bumps for ease of manufacturing) angularlyspaced relative to each other about the axis of the plug, and anaperture 228 extending through the side wall for allowing fluidcommunication between the interior chamber 180 of the bladder and theambient atmosphere. The tapered portion 220, because of the increasingdiameter thereof, provides for ease of assembly of the plug 214 to theflexible bladder 54 (FIG. 2) and defines an annular space 230 (FIG. 2)located between the plug and the adjacent surface of the flexiblebladder. As described above and shown in FIGS. 2 and 3, the annulargroove 222 is configured to receive the inner annular lobe 192 (FIG. 10)and the stepped portion 224 sandwiches the annular flange 188 of theflexible bladder 54 against the annular ridge 172 of the rigid vial. Asbest seen in FIGS. 13 and 14, the safety sealing tabs 226 projectupwardly and outwardly from the stepped portion 224 and are angularlyspaced relative to each other about the axis of the plug. The sealingtabs 226 are provided for locking the plug 214 to the vial 52 (FIG. 2)and are configured to snap-fit within the annular groove 168 of the vial(FIG. 9) upon being pressed against the annular flange 188 of thebladder to thereby maintain an airtight seal. In addition, because thesealing tabs 226 are tapered outwardly as shown typically in FIG. 14A,the tabs easily snap into the annular groove 168 of the vial; however,the tabs cannot be moved out of the groove in the opposite direction andthereby form a tamper-proof seal. The aperture 228 provides for fluidcommunication between the annular space 230, chamber 180 (FIG. 2) andambient atmosphere, and is illustrated as being generally rectangular inconfiguration. However, it will be understood that other configurations,such as circular or other shapes, may be employed, providing that asufficient volume of air may pass therethrough to fill the interiorchamber 180 of the flexible bladder 54.

[0095] Returning to FIGS. 10 and 10A, the flexible bladder 54 alsopreferably comprises a two-way valve 234 axially spaced below thesealing lobes 190 and 192 for controlling the flow of air between theinterior chamber 180 of the bladder and ambient atmosphere. The valve234 comprises an annular operator 235 projecting inwardly from theinterior wall of the bladder and having a generally ridge-likeconfiguration in cross section. As shown in FIGS. 2 and 3, the endportion of the annular operator 235 engages the annular surface 232formed at the base of the rear plug 214, and is disposed between theannular space 230 and the interior chamber 180 of the bladder. Theflexible bladder 54 further defines a plurality of support protuberances236 that are axially spaced adjacent to the annular operator 235 andangularly spaced relative to each other about the axis 202. The endsurface of each protuberance 236 is spaced inwardly relative to the endof the annular operator 235 to thereby allow the operator 235 to engageand seal the interface between the operator and rear plug, whilesimultaneously ensuring sufficient radial spacing between the rear plugand flexible bladder for allowing movement of the operator 235 in eitherdirection. Thus, as can be seen, the operator 235 and annular wall 232of the rear plug form a two-way valve allowing fluid to flowtherethrough when the differential pressure across the valve issufficient to axially flex the operator. It will be understood that therigidity of the operator is set to allow fluid to pass therethrough whenthe pressure differential exceeds a predetermined threshold pressure.Thus, a significant advantage of the valve 234 is that it maintains arelatively stable micro-atmosphere within the inner chamber 180 of theflexible bladder 54 and prevents a regular exchange of air, other gasesor vapors between the micro-atmosphere within the bladder and theambient atmosphere. For example, the valve 234 allows air to be drawninto the chamber 180 upon dispensing the medicament or other substancefrom the main fluid chamber 55 to thereby allow the bladder to expandand fill the space of the dispensed medicament. However, the valve 234otherwise prevents air or vapors from flowing freely between themicro-atmosphere and the ambient atmosphere. Thus, the micro-atmospherewithin the chamber 180 may define different pressure and/or humiditylevels in comparison to the ambient atmosphere. A significant advantageof this feature is that it insulates the micro-atmosphere fromfluctuations in the pressure and/or humidity levels of the ambientatmosphere, thereby maintaining relatively stable pressure and humiditylevels within the micro-atmosphere and thus preventing the ingress ofair or vapors through the bladder wall and into the main fluid chamber.

[0096] In FIGS. 15A-15C, the dispenser 10 is illustrated in the full,half-full and empty conditions, respectively. In FIG. 15A, the mainfluid chamber 55 is filled with, e.g., a medicament (not shown) that thepump assembly 50 may pump outwardly of the nozzle 58. Accordingly, thebladder 54 is illustrated in a collapsed state. In FIG. 15B, theflexible bladder 54 is shown in an expanded condition whereby thebladder has expanded to displace the volume of medicament dispensed fromthe main fluid chamber 55. To achieve this result, air has passed in thedirection of arrow 240, through the valve 234 and into the interiorchamber 180 of the flexible bladder. In FIG. 15C, the dispenser 10 isillustrated in an empty condition. As can be seen, the bladder 54 isfully expanded against wall 77 of the rigid vial and substantiallyconforms to the morphology of the rigid vial to thereby eliminate anyullage or dead space and force all medicament or other substancestherein into the pump 50.

[0097] Referring now to FIGS. 16A-16C, initial assembly of the dispenser10 for purposes of sterilization, e.g., by irradiation of energy rays,is illustrated in FIG. 16A. In particular, the rear plug 214 is fittedto the flexible bladder 54, and the plug and flexible bladder arepartially inserted into the vial 52. Turning now also to FIGS. 9A and10, the flange 188 of the flexible bladder 54, when in the partiallyinserted position, is disposed within the annular groove 168 of the vial52 to thereby form an air-tight, but not a tamper-proof seal between thebladder and vial. In this state, the dispenser 10 may be sterilizedand/or transported in a sealed condition prior to filling the dispenserwith a medicament or other substance to be contained therein.

[0098] The filling of the dispenser 10 is illustrated schematically inFIG. 16B, wherein the flexible bladder 54 and plug 214 are separatedfrom the vial 52 so that the main fluid chamber 55 may be accessed forfilling. As can be seen, the annular flange 188 of the bladder may bepulled rearwardly and removed from the annular groove 168 of the vial tothereby open the vial and access the main fluid chamber 55. Preferably,this operation is carried out by transporting the sterilized dispensersthrough a sterile transfer port, and filling the dispensers within asterile filling machine of the types disclosed in commonly-assigned U.S.Pat. Nos. 5,641,004 and 5,816,772, which are hereby expresslyincorporated by reference as part of the present disclosure. Duringfilling, a vacuum may be drawn on the inner chamber 180 of the bladderto collapse the bladder, and the medicament or other substance to becontained therein may be introduced into the main fluid chamber 55.

[0099] As shown in FIG. 16C, upon filling the main fluid chamber 55 withthe medicament or other substance to be contained therein, the flexiblebladder and rear plug assembly are moved into the rigid vial such thatthe flexible flange 188 of the bladder is moved into engagement with theannular ridge 172, best seen in FIG. 9A, and the rear plug is pressedinwardly until the sealing tabs 226 are snapped into place within theannular groove 168 of the vial to thereby form the airtight andtamper-proof seal. The dispenser 10 may then be installed within theocular treatment apparatus 8 described above or other suitable apparatusfor dispensing medicaments or other fluids, such as nasal inhalers.

[0100] In FIGS. 17 through 20, another embodiment of the dispenser ofthe present invention is indicated generally by the reference numeral310. The dispenser 310 is substantially similar to the dispenser 10described above, and therefore like reference numerals preceded by thenumeral “3”, or preceded by the numeral “4” instead of the numeral “1”,or preceded by the numeral “5” instead of the numeral “2”, respectively,are used to indicate like elements. The primary differences of thedispenser 310 in comparison to the dispenser 10 are that (i) the rigidvial 352 and piston 356 are formed as integral components; (ii) thenozzle 358 and slide 360 are formed as integral components; (iii) theflexible bladder 354 defines a smooth cylindrical configuration withoutany discontinuities or ribs formed thereon; and (iv) the rear plug 514includes a plurality of inwardly projecting legs 538 for controlling thecollapse of the flexible bladder into a predetermined collapsed shape.

[0101] As shown in FIGS. 21-23, the rear plug 514 defines a plurality ofinwardly projecting, axially-elongated legs 538 defining a frameworkwithin the interior chamber 480 of the flexible bladder 354 forcontrolling the collapse of the bladder into a predetermined collapsedshape. As shown in FIG. 21, the currently preferred embodiment of thepresent invention includes three legs 538 angularly spaced approximately120° relative to each other about the axis of the rear plug. Each leglies in a respective plane intersecting the axis of the rear plug anddefines approximately planar side surfaces 540 extending radiallybetween the axis of the plug and the inner wall of the rigid vial. Asshown in FIGS. 19 and 20, the radial edge 542 of each leg is radiallyspaced inwardly relative to the inner wall of the rigid vial to therebyallow movement of the flexible bladder between the radial edges of thelegs and the vial. As also shown in FIGS. 19 and 20, the legs 538 extendaxially into the interior chamber 480 of the flexible bladder a distancesufficient to allow the legs to control the collapse of the bladder intothe predetermined collapsed condition. In the illustrated embodiment,each leg 538 extends along at least about one-half the axial extent ofthe bladder. As shown in FIG. 24, in the predetermined collapsedcondition, the flexible bladder 354 conformably engages the outersurfaces of the legs 538 to thereby allow the main fluid chamber 355 tobe filled with a medicament or other substance. Then, as shown in FIG.25, upon dispensing all of the medicament or other substance from themain fluid chamber 355, the resilient nature of the flexible bladder 354causes the bladder to expand outwardly away from the legs 538. As showntypically in FIGS. 19 and 20, when fully expanded, the flexible bladder354 conformably engages the inner wall of the rigid vial to therebyeliminate any ullage or dead space and allow all of the medicament orother substance contained with the main fluid chamber 355 to bedispensed therefrom.

[0102] As described above, the flexible bladder 538 is preferably madeof a relatively low permeability elastomer, such as a vulcanized butylrubber, or other rubbers. Such rubbers have demonstrated provenstability and/or compatibility with a wide variety of medicaments, suchas pharmaceutical preparations and vaccines, and other substances, andtherefore are currently preferred for such applications. In thecurrently preferred embodiment, the flexible bladder 354 is molded inits expanded condition, and when collapsed, the resilient nature of thebladder tends to force the bladder outwardly toward its expandedcondition. The resilient forces within the bladder apply a pressureagainst the fluid within the main fluid chamber 355, and thereforecreate a higher pressure in the main fluid chamber 355 in comparison tothat of the interior chamber 480 of the bladder. As a result, thepressure differential prevents the ingress of air or other gases orvapors through either the flexible bladder or rigid vial, or otherwiseinto the main fluid chamber. Thus, the material and/or configuration ofthe bladder are preferably selected to maintain a pressure differentialsufficient to prevent the ingress of air or other gases or vapors intothe main fluid chamber under a variety of atmospheric conditions. Asdescribed above, the preferred rubber materials disclosed herein forconstructing the flexible bladder are exemplary, and numerous othermaterials that are currently, or later become known for performing thefunction of the flexible bladder may be equally employed.

[0103] As shown in FIGS. 26 and 27, the spaced protuberances 236described above in connection with the flexible bladder 54 of FIG. 10Amay be eliminated depending upon the material of construction and/orother structural features of the flexible bladder 354. In addition, theouter annular lobe may take a shape different than that illustratedabove in connection with the bladder of FIG. 10A. As shown in FIG. 27,the outer annular lobe 490 is defined by an annular raised or thickenedportion, and a tapered surface 498 extending radially inwardly betweenthe lobe or annular raised portion 490 and the outer peripheral surfaceof the flexible bladder 354. As shown in FIGS. 19 and 20, the annularraised portion 490 is squeezed against the inner surface of the rigidvial 352 which, in combination with the axially offset, inner annularlobe 492 being fixedly received within the annular groove 522 of therear end cap (FIG. 23), cause the material of the flexible bladder tocreep and/or otherwise flow in the directions of the arrows 504 and 505in FIG. 27 to thereby persistently maintain an airtight seal between theflexible bladder, rear plug and rigid vial. Thus, the end seal of theflexible bladder is both radially compressed at the axially offset lobesbetween the rear plug and rigid vial, and is axially compressed at theflange between the rear plug and rigid vial.

[0104] As shown typically in FIG. 22, the rear plug 514 defines threeapertures 528 approximately equally spaced relative to each other aboutthe axis of the plug. In addition, rather than defining the sealing tabs226 described above in connection with FIG. 14, the rear plug 514defines an annular lobe 526 projecting outwardly from the peripheralsurface of the rear plug and dimensioned to be snapped into the annulargroove 168 of the rigid vial (FIG. 30). The dispenser 310 may besterilized, temporarily closed, re-opened, and filled in the same manneras described above in connection with FIGS. 16A through 16C.

[0105] As shown in FIGS. 28 and 29, the nozzle 358 and slide 360 areformed integral with each other. One advantage of this construction overthe separate nozzle and slide described above in connection with theprevious embodiment, is that the integral construction is typically lesscostly to manufacture and assemble, and furthermore, reduces the numberof seals between components and thereby enhances the overall reliabilityof the dispenser.

[0106] As shown in FIGS. 30 and 31, the piston 356 and rigid vial 352are also formed integral with each other. As with the integral nozzleand slide described above, one advantage of this construction over theseparate piston and slide described above in connection with theprevious embodiment, is that the integral construction is typically lesscostly to manufacture and assemble, and furthermore, reduces the numberof seals between components and thereby enhances the overall reliabilityof the dispenser. In the currently preferred embodiment of the presentinvention, the integral nozzle 358 and slide 360 is made of a relativelysoft material, and the integral piston 356 and vial 352 is made of arelatively hard material. In the operation of the dispenser 310, on thedownward stroke of the piston 356, and upon reaching the compressionzone 436 of the slide 360, the relative hardness and geometry of theillustrated piston causes the piston to force the compression zone 436of the slide outwardly and thereby form a fluid-tight seal between thepiston and slide. As illustrated in FIG. 30, the tip of the guide wall394 defines a chamfer for facilitating sliding movement of the pistonwithin the slide.

[0107] Forming the integral nozzle and slide of a relatively soft and/orflexible material allows the compression zone 436 of the slide to flexoutwardly in order to remove the part from a core pin upon molding thepart, and thus enables the nozzle and slide to be integrally molded as asingle part. Preferably, compressed air is injected between the core pinand interior surface 392 of the slide to facilitate removal of the partfrom the core pin (not shown).

[0108] As shown in FIGS. 19 and 20, when the flexible bladder 354 is ator near its fully-expanded condition, an annular gap “C” is formedbetween the bladder and vial. As can be seen, the width of the gap Cgradually increases in the axial direction moving from the rear end cap514 toward the closed end 476 of the bladder. As can be seen, the gap Cstarts about half-way down the axial extent of the bladder and reachesits maximum width at the curved portion of the bladder between the sidewall and end wall 476. The gap C may be created by forming theapproximately cylindrical side wall of the flexible bladder 354 with asufficient draft to form the gap upon insertion of the bladder into therigid vial. The purpose of the gradually-increasing gap C is to forceall fluid within the main fluid chamber 355 in the direction toward thepump 350 and prevent the formation of any pockets of fluid within themain fluid chamber that cannot be dispensed therefrom.

[0109] As shown typically in FIGS. 19 and 20, other than the slightdifferences necessary to create the gap C, the flexible bladder 354defines approximately the same morphology as the interior surfaces ofthe rigid vial 352, thus enabling intimate and conforming engagement ofthe bladder with the rigid vial upon full expansion of the bladder. Inaddition, the flexible bladder 354 preferably defines in its fullyexpanded condition an outer diameter (or width) at least equal to orgreater than the inner diameter (or width) of the chamber 355 of therigid vial. These features, in combination with the resilient nature ofthe flexible bladder, prevent the ingress of gases or vapors into themain fluid chamber 355, and ensure usage of substantially all fluidcontained within the chamber.

[0110] As shown in FIG. 32, the flexible cover 362 defines an annularmounting flange 380 on one end thereof which is received within acorresponding annular groove 374 formed on the integral piston and rigidvial (FIGS. 30 and 31) to fixedly secure the flexible cover thereto. Inaddition, the integral piston and rigid vial defines an annular flange381 adjacent to the annular groove 374 which is received within acorresponding annular groove 382 of the flexible cover (FIG. 32) tofurther secure the cover thereto.

[0111] Turning to FIG. 33, another embodiment of the dispenser of thepresent invention is indicated generally by the reference numeral 610.The dispenser 610 is substantially the same as the dispenser 310described above, and therefore like reference numerals preceded by thenumeral “6” instead of the numeral “3”, the numeral “7” instead of thenumeral “4”, or the numeral “8” instead of the numeral “5”,respectively, are used to indicate like elements. The primary differenceof the dispenser 610 in comparison to the dispenser 310 is that thedispenser 610 includes a resealable bladder to allow the bladder to befilled in a sterile filling machine of the type disclosed in co-pendingU.S. patent application Ser. No. 09/781,846, filed Feb. 12, 2001, whichis assigned to the same Assignee as the present invention, and is herebyexpressly incorporated by reference as part of the present disclosure.

[0112] As shown in FIG. 33, the flexible bladder 654 includes on itsclosed end 776 a resealable portion 844 overlying the closed end 776. Inthe illustrated embodiment, the flexible bladder 354 is formed of afirst material compatible with the predetermined medicament or othersubstance to be contained within the main fluid chamber 655, and defineson its external side a medicament-exposed surface intended to be exposedor otherwise placed in contact with the predetermined medicament orother substance contained within the main fluid chamber. The resealableportion 844 is penetrable by a needle or like filling member forintroducing the predetermined medicament or other substance through theflexible bladder and into the main fluid chamber. The penetrable regionof the flexible bladder is formed of a vulcanized rubber, and thereforeis substantially infusible in response to the application of thermalenergy thereto. The penetrable region of the resealable portion 844, onthe other hand, is fusible in response to the application of thermalenergy thereto, thus allowing the penetrable region of the resealableportion to be hermetically sealed upon removing the needle or likefilling member therefrom. In the illustrated embodiment, the resealableportion 844 is insert molded onto the rubber bladder during which thethermoplastic resealable layer bonds itself to the underlying rubberlayer. If necessary, a mechanical fastener of a type known to thoseskilled in the pertinent art may be used to facilitate attachment of theresealable portion to the end wall of the flexible bladder.

[0113] The resealable member 844 is preferably made of a resilientpolymeric material, such as a blend of the polymeric material sold byGLS under the registered trademark KRATON® and a low-densitypolyethylene, such as the polyethylene sold by Dow Chemical Co. underthe trademarks ENGAGE™ or EXACT™. An important feature of the resealablemember 844 is that it be resealable to form a gas-tight seal afterinserting a needle, syringe or like injection member through theresealable member. Preferably, the resealable member can be sealed byheating the area punctured by the needle in a manner known to thoseskilled in the pertinent art and described in the above-mentionedco-pending patent application. One advantage of the blended polymerdescribed above is that it is known to minimize the degree to which themedicament or other substance can be absorbed into the polymer incomparison to KRATON® itself.

[0114] As shown in FIG. 33, the rear plug 514 defines a filling aperture846 formed therethrough and overlying the resealable member 844. Asshown in broken lines in FIG. 33, a double lumen needle or likeinjection member 848 may be reciprocally moved through the fillingaperture 846 to, in turn, pierce both the resealable member 844 andunderlying closed end 776 of the flexible bladder. The injection member848 is coupled in fluid communication with a source (not shown) ofmedicament or other substance to be contained within the main fluidchamber 655 and is actuated to fill the chamber with the medicament orother substance. Upon filling the chamber, the flexible bladder 654 iscollapsed into its predetermined collapsed condition, as shown above,and the needle is withdrawn. If necessary, a vacuum may be drawn on theinterior chamber 780 of the flexible bladder during filling tofacilitate collapse of the bladder. Upon withdrawing the needle, a laseror other energy source (not shown) transmits a beam of laser radiationonto the penetrated region of the resealable member to seal the needlehole in the manner described in the above-mentioned co-pending patentapplication and thereby maintain the medicament or other substancecontained therein in a sterile, hermetically sealed condition. Thefilling aperture 846 may be sealed with a cap 850 (shown in brokenlines) to maintain the interior chamber 780 of the flexible bladder in asealed condition.

[0115] As may be recognized by those skilled in the pertinent art basedon the teachings herein, numerous changes and modifications may be madeto the above-described and other embodiments of the present invention,without departing from its scope as defined in the appended claims.Accordingly, this detailed description of preferred embodiments is to betaken in an illustrative, as opposed to a limiting sense.

What is claimed is:
 1. A dispenser for dispensing a fluid, comprising: arigid housing; a flexible bladder mounted within the housing anddefining an interior chamber within the flexible bladder, and afluid-receiving chamber between the flexible bladder and the rigidhousing; and first means for creating a first pressure within thefluid-receiving chamber greater than a second pressure within theinterior chamber of the bladder and thereby preventing the ingress ofgases or vapors into the fluid-receiving chamber.
 2. A dispenser asdefined in claim 1, further comprising: a pump coupled in fluidcommunication with the fluid-receiving chamber for pumping a fluidreceived therein from the dispenser; and a one-way valve coupled influid communication with the pump for allowing the passage of the pumpedfluid therethrough and preventing the passage of fluids in the oppositedirection.
 3. A dispenser as defined in claim 1, wherein the flexiblebladder is movable between a collapsed condition upon filling thefluid-receiving chamber with a fluid and an expanded condition upondispensing the fluid from the fluid-receiving chamber.
 4. A dispenser asdefined in claim 3, wherein the first means is formed by a resilientmaterial of the bladder that flexes the bladder outwardly toward theexpanded condition and thereby creates the first pressure within thefluid-receiving chamber greater than the second pressure in the interiorchamber of the bladder.
 5. A dispenser as defined in claim 1, furthercomprising: a seal formed between the flexible bladder and rigid vialfor sealing the fluid-receiving chamber, wherein the seal includes afirst protuberance extending radially outwardly on an outer surface ofthe flexible bladder, and a second protuberance axially spaced relativeto the first protuberance and extending radially inwardly on an innersurface of the bladder, and the first and second protuberances aresubject to radial compression to seal the interface between the flexiblebladder and rigid vial.
 6. A dispenser as defined in claim 5, whereinthe first protuberance extends about an outer peripheral surface of thebladder and defines an outer annular sealing surface, and the secondprotuberance extends about an inner peripheral surface of the bladderand defines an inner annular sealing surface.
 7. A dispenser as definedin claim 6, wherein the first protuberance defines a tapered surface fordirecting bladder material in approximately the direction of the secondprotuberance to thereby facilitate maintaining a fluid-tight seal in theevent of bladder material creep.
 8. A dispenser as defined in claim 7,wherein the tapered surface is curved.
 9. A dispenser as defined inclaim 5, wherein the seal further includes a peripheral flange extendingabout an open end of the bladder and subject to axial compression forfurther sealing the interface between the bladder and rigid vial.
 10. Adispenser as defined in claim 5, further comprising a plug receivablewithin an open end of the rigid vial and engageable with at least one ofthe first and second protuberances for radially compressing the at leastone protuberance to seal the interface between the flexible bladder andrigid vial.
 11. A dispenser as defined in claim 10, wherein the plugdefines an annular surface engageable with the second protuberance forradially compressing the second protuberance and thereby sealing theinterface of the flexible bladder and rigid vial.
 12. A dispenser asdefined in claim 1, further comprising a plug receivable within an openend of the rigid vial.
 13. A dispenser as defined in claim 12, furthercomprising a seal formed between the plug and rigid vial, and whereinthe plug defines at least one aperture therethrough in fluidcommunication with the interior chamber of the flexible bladder.
 14. Adispenser as defined in claim 13, further comprising a two-way valvecoupled in fluid communication between the interior chamber of theflexible bladder and the aperture of the plug for preventing fluidcommunication between the interior chamber of the bladder and theambient atmosphere when a pressure differential across the two-way valveis less than a threshold level.
 15. A dispenser as defined in claim 14,wherein the two-way valve is formed by a flexible, annular protuberanceextending radially inwardly from an inner peripheral surface of theflexible bladder and engageable with an annular surface of the plug tothereby seal the interface between the flexible bladder and plug.
 16. Adispenser as defined in claim 15, wherein the annular protuberancedefines axially-opposed surfaces that taper inwardly in the radialdirection to facilitate flexing of the protuberance in response to apressure differential across the protuberance exceeding a predeterminedthreshold level.
 17. A dispenser as defined in claim 1, wherein theflexible bladder defines at least one radially compressible sealingsurface, and at least one axially compressible sealing surface axiallyspaced relative to the at least one radially compressible sealingsurface for effecting both axially and radially directed seals.
 18. Adispenser as defined in claim 17, wherein the flexible bladder definestwo radially compressible sealing surfaces, and wherein a first radiallycompressible sealing surface is located on an external peripheralsurface of the flexible bladder, and a second radially compressiblesealing surface is located on an internal peripheral surface of thebladder, and the first and second radially compressible sealing surfacesare axially offset relative to each other.
 19. A dispenser as defined inclaim 18, wherein the first radially compressible sealing surfacedefines a tapered surface portion for directing bladder material inapproximately the direction of the second radially compressible sealingsurface to facilitate maintaining a fluid-tight seal in the event ofbladder material creep.
 20. A dispenser as defined in claim 1, whereinthe flexible bladder defines an open end and a closed end, and ismovable between a collapsed condition and an expanded condition, whereinupon expansion of the flexible bladder from the collapsed condition intothe expanded condition, the flexible bladder and rigid vial define anannular gap therebetween, and the annular gap defines an increasingwidth in the axial direction from the open end toward the closed end ofthe flexible bladder to facilitate the removal of fluid from thefluid-receiving chamber upon expansion of the flexible bladder.
 21. Adispenser as defined in claim 20, wherein upon expansion of the flexiblebladder from the collapsed condition into the expanded condition, theflexible bladder initially contacts the rigid vial adjacent to the openend of the flexible bladder, and the flexible bladder progressivelyengages the rigid vial in the axial direction from the open end towardthe closed end of the flexible bladder with further expansion thereof.22. A dispenser as defined in claim 1, wherein the flexible bladderdefines an external morphology in an expanded condition, the rigid vialdefines an internal morphology, and the external and internalmorphologies are substantially the same to thereby allow the flexiblebladder to conformably contact the rigid vial and substantiallyeliminate any dead space in the fluid-receiving chamber therebetween.23. A dispenser as defined in claim 1, wherein the flexible bladder ismade of a resilient material and defines an outer width in an expandedcondition, the rigid vial defines an inner width, and the outer width ofthe bladder is at least equal to or greater than the inner width of therigid vial to thereby allow the resilient bladder to exert pressure onthe fluid-receiving chamber and rigid vial upon expanding into contacttherewith.
 24. A dispenser as defined in claim 1, further comprising: apiston; and a slide for slidably receiving the piston therein, whereinat least one of the piston and the slide is reciprocable relative to theother, and the piston is made of a relatively hard material, the slideis made of a relatively soft material, and the piston flexes at least aportion of the slide outwardly upon moving at least one of the pistonand the slide relative to the other.
 25. A dispenser as defined in claim24, wherein the piston and rigid vial are formed integral with eachother as a single part.
 26. A dispenser as defined in claim 24, furthercomprising a nozzle coupled in fluid communication with the slide forreceiving fluid pumped therethrough by the piston, and wherein thenozzle and slide are formed integral with each other as a single part.27. A dispenser as defined in claim 1, further comprising: a plugdefining at least one peripheral protuberance; and wherein the flexiblebladder defines a peripheral flange, and the rigid vial defines an openend and a recess spaced axially inwardly from the open end, and whereinthe peripheral flange of the flexible bladder is receivable within therecess for temporarily sealing the fluid-receiving chamber, and the atleast one peripheral protuberance is receivable within the recess upondepressing the plug axially inwardly into the rigid vial to therebysecure the plug and bladder to the vial.
 28. A dispenser as defined inclaim 27, wherein upon engaging the at least one peripheral protuberancewith the recess of the vial, the plug axially compresses the peripheralflange to seal the fluid-receiving chamber formed between the flexiblebladder and rigid vial.
 29. A dispenser as defined in claim 1, whereinthe flexible bladder is movable between an expanded condition and apredetermined collapsed condition, and the dispenser further comprisesmeans for controlling the bladder to collapse into the predeterminedcollapsed condition.
 30. A dispenser as defined in claim 29, wherein themeans for controlling includes a plurality of legs extending axiallyinwardly into the interior chamber of the flexible bladder forconformably contacting the flexible bladder upon collapse thereof.
 31. Adispenser as defined in claim 29, wherein the means for controllingincludes at least one axially elongated surface discontinuity formed inthe flexible bladder.
 32. A dispenser as defined in claim 31, whereinthe means for controlling further includes at least one axiallyelongated rib formed on the flexible bladder and angularly spacedrelative to the at least one surface discontinuity.
 33. A dispenser asdefined in claim 1, wherein the bladder is capable of being penetratedby a needle or like injection member for introducing a predeterminedsubstance into the fluid-receiving chamber, and the bladder includes afirst portion substantially infusible in response to the application ofthermal energy thereto and compatible with the substance to be receivedwithin the fluid-receiving chamber, and a second portion overlying thefirst portion and fusible in response to the application of thermalenergy thereto for forming a substantially fluid-tight seal between theflexible bladder and fluid-receiving chamber in a region thereofpenetrable by the needle or like injection member.
 34. A dispenser asdefined in claim 33, wherein the second portion is formed of at leastone of a thermoplastic and an elastomeric material.
 35. A dispenser asdefined in claim 33, wherein the first portion is formed of vulcanizedrubber.
 36. A dispenser for dispensing a fluid, comprising: a rigidhousing; a flexible bladder mounted within the housing and defining aninterior chamber within the flexible bladder, and a fluid-receivingchamber between the flexible bladder and the rigid housing, wherein theflexible bladder is movable between a collapsed condition upon fillingthe fluid-receiving chamber with a fluid, and an expanded condition upondispensing the fluid from the fluid-receiving chamber, and is formed ofa resilient material that flexes the bladder outwardly toward theexpanded condition and, in turn, creates a first pressure within thefluid-receiving chamber greater than a second pressure in the interiorchamber of the bladder to thereby prevent the ingress of gases or vaporsinto the fluid-receiving chamber; a pump coupled in fluid communicationwith the fluid-receiving chamber for pumping a fluid received thereinfrom the dispenser; and a one-way valve coupled in fluid communicationwith the pump for allowing the passage of the pumped fluid therethroughand preventing the passage of fluids in the opposite direction.
 37. Adispenser for dispensing a fluid, comprising: a rigid housing definingtherein an enclosure; first means mounted within the enclosure of thehousing for forming an expandable and collapsible first fluid-receivingchamber on one side thereof, and an expandable and collapsible secondfluid-receiving chamber on another side thereof; second means forcreating a first pressure within the first fluid-receiving chambergreater than a second pressure within the second fluid-receiving chamberand thereby preventing the ingress of gases or vapors into the firstfluid-receiving chamber; and third means coupled in fluid communicationwith the first fluid-receiving chamber for pumping fluid therefrom; andfourth means coupled in fluid communication with the third means forallowing the fluid to be dispensed therefrom and preventing any fluidfrom flowing therethrough in the opposite direction.
 38. A dispenser asdefined in claim 37, wherein the first means is defined by a flexiblebladder mounted within the enclosure of the housing and defining thesecond fluid-receiving chamber within the flexible bladder, and thefirst fluid-receiving chamber between the flexible bladder and the rigidhousing.
 39. A dispenser as defined in claim 37, wherein the secondmeans is formed by a resilient material of the first means that flexesthe first means outwardly toward the expanded condition and therebycreates the first pressure within the first fluid-receiving chambergreater than the second pressure in the second fluid-receiving chamber.40. A dispenser as defined in claim 37, further comprising means forcontrolling the first means to collapse into a predetermined collapsedcondition.